It is known that honeybees, Apis Mellifera, may be plagued by parasitic mites and in particular by Varroa mites, Varroa Jacobsoni. The parasite feeds from the bees blood after attaching itself firmly to the body. A large shield-like hard casing protects the Varroa's vulnerable underside. Once attached, the parasite is virtually untouchable within the bee hive environment. Once inside the hive, other bees are quickly affected. Blood loss leads to lethargy, and with a decline in worker bees collecting pollen, the honey output declines. The hive itself can be completely wiped out in some cases within a few months. Conventionally, control of such parasitic mites in bee hives has been by mechanical evaporative distribution of formic acid, or by the use of pesticides such as Apistan.TM. (active ingredient Fluvalinate) or Taktivar.TM. (active ingredient Armitraz). The formic acid method of control of parasitic mites is typically laborious, requiring repeated maintenance and replenishment. The pesticide method of control of parasitic mites results in the mites building up a resistance to such pesticides, reducing their effectiveness.
Consequently, it is an object of the present invention to provide for the treatment of honeybees against Varroa mites by the use of a biological control namely the use of the acarine parasite Hirsutella thompsonii.
Commercially, Hirsutella thompsonii may be found as the active ingredient of a mycoacaricide, at one time produced under the trade-marks Mycar.TM. and, earlier, ABG6065, by Abbott Laboratories of North Chicago, Ill., U.S.A. As reported by McCoy and Couch in their publication entitled "Microbial Control of the Citrus Rust Mite with the Mycoacaricide, Mycar.RTM." (the Florida Entomologist, Volume 65, Number 1, March 1982), Mycar.TM. as a wetable powder or dust was effective in stimulating premature fungal epizootics in citrus rust mite, Phyllocoptruta oleivora, populations in Valencia orange groves in central and south Florida. Hirsutella thompsonii, the active ingredient of Mycar.TM., was established on treated fruit and foliage via the particulate residue which supplied a substrate for mycelial growth and subsequent conidiogensis by the fungus. McCoy reported excellent crop protection was achieved with Mycar.TM. and a Mycar-oil combination in field trials.
McCoy and O'Donnell in their publication "Taxonomy of the Acarine Parasite Hirsutella thompsonii" (Mycologia, Volume LXXII, No. 2, pages 359-377, March-April, 1980) report that Hirsutella thompsonii is an important fungal pathogen of the citrus rust mite and other eriophyoid mites and that Hirsutella thompsonii appears to be a specific pathogen of various species of Acari which inhabit a wide range of plants throughout the world. These are plant mites, not mites on living organisms. The prior art does not report finding these mites on living organisms.
Gerson et al report ("Hirsutella thompsonii, a fungal pathogen of mites" Appl Biol (1979), 91, 29-40) that plant feeding mites are susceptible to Hirsutella thompsonii but that other mite orders were not infected by Hirsutella Thompsonii suggesting specificity of this fungus for one mite order--the Prostigmata.
What is neither taught nor suggested in the prior art and which is the subject of the present invention, is that Hirsutella thompsonii in the form of dust, wetable powder, liquid, or other carrying transfer media, may be used against mites on living organisms, specifically mites on honeybees, for example, by being applied into the honeybee's brood nest or food supply, and when so applied acts as a pathogen against a living organism, in particular, the Varroa mite which feeds on other living organisms, i.e. honeybees, rather than against other mites which feeds on plants and fruit.